Fiber-optical connector system

ABSTRACT

The invention relates to a fiber-optical connector system, comprising a fiber-optical connector ( 10 ) and a coupling into which the connector ( 10 ) can be inserted to establish an optical connection. The connector ( 10 ) has a housing ( 11 ) that extends along an axis ( 49 ) and in which an optical fiber is arranged aligned with said axis ( 49 ) and projects with one end from the face of the housing ( 11 ). Means ( 30, 32 ) cover the end of the optical fiber and protect the end of the optical fiber from any effects from the exterior when the connector ( 10 ) is not inserted and release the end of the optical fiber projecting from the housing ( 11 ) when the connector ( 10 ) is inserted in the coupling ( 40 ). A reliable and space-saving cover and protection device for a connector system can be achieved by configuring the cover means ( 30, 32 ) with a first cover element ( 32 ) that protects the end of the optical fiber in the axial direction and that can be displaced at an angle to the axis ( 49 ). A second cover element ( 30 ) protects the end of the optical fiber projecting from the housing ( 11 ) in the radial direction and can be pushed backwards parallel to the axis ( 49 ). Said second cover element has a first passage ( 36 ) for the end of the optical fiber which can be closed by the first cover element ( 32 ).

TECHNICAL FIELD

[0001] The present invention relates to the field of fiber optics. Itconcerns a fiber-optical connector system according to theprecharacterizing clause of claim 1.

[0002] Such a system is known for example from the printed documentsWO-A1-00/16145 or EP-B1-0 570 652.

PRIOR ART

[0003] In the case of fiber-optical connector systems, in which it isusual for two optical fibers to be releasably connected to each other byinsertion of two connectors into a coupling from two sides, the endfaces of the two fibers to be connected must be brought into contact insuch a way that a transfer of the optical signals that is as free aspossible from losses can take place between the two fibers. For thispurpose, the ends of the optical fibers, which are often adhesivelyembedded in ferrules, enter from both sides into a guiding sleeveprovided in the coupling (see for example FIG. 10 of EP-B1-0 570 652 orFIGS. 20 and 21 of WO-A1-00/16145). In order that this can take place,the ends of the optical fibers or ferrules must be freely accessible atthe end of the insertion operation.

[0004] On the other hand, it is necessary to prevent the ends of theoptical fibers from being soiled when the connectors are not inserted inthe coupling. In principle, it is conceivable for this purpose toprovide protective caps, which are pushed manually over the free ends ofthe connectors. In order to avoid incorrect operation, however, a changehas taken place in favor of providing the connectors with covering meanswhich open automatically when the connector is inserted into thecoupling, and also close again automatically when the connector ispulled out of the coupling. In addition, the coupling means are set upin such a way that a light beam emerging from the free fiber ends isreliably covered and cannot cause any damage.

[0005] In WO-A1-00/16145 (ADC) there is a description of a fiber-opticalconnector system which comprises a connector and a coupling. Theconnector, in which the optical fiber guided in the interior mayoptionally be arranged with its end freely accessible (FIGS. 5, 9) or ina ferrule (FIGS. 10, 13), is equipped with a covering flap. The coveringflap is mounted pivotably about a fixed pivot axis. It pivots oninsertion of the connector into the coupling, when an actuating camarranged in the coupling comes into engagement with a slotted guidewayon the covering flap. The covering flap and its pivoting region aredesigned in such a way that, after pivoting up, an end portion of theoptical fiber or of the ferrule enclosing it projects freely forward outof the connector housing and can enter a sleeve-like guiding partarranged in the coupling. However, this has the consequence thatcomparatively considerable space is required for accommodating thecovering flap on that side toward which the covering flap pivots up.This also applies to a similar known solution with a fixed pivot axis,as disclosed in U.S. Pat. No. 5,379,362.

[0006] Another known solution. (EP-B1-0 570 652, Diamond S. A.) providesa covering flap which, when the connector is inserted into the coupling,in a first phase is pivoted up by about 90° and in a second, subsequentphase is pushed back rearward parallel to the pivot axis, in order torelease completely the end of the ferrule projecting from the connectorhousing. Although the combined pivoting and pushing movement has theeffect that the space requirement for the covering flap is less than inthe case of the pure pivoting movement of WO-A1-00/16145, the combinedmovement represents a comparatively complicated sequence of movements,which requires high precision and is susceptible to malfunctions. Inaddition, here—as in the case of the solution according toWO-A1-00/16145—the covering flap can be inadvertently opened and remainopen even when a connector is not inserted.

[0007] A further known solution for a covering or protecting mechanismoperating automatically on insertion is described in GB-A-2,112,173(Thomas and Betts Corp.). In the case of this fiber-optical connector,the fiber lies with its end in a guiding sleeve which projects forwardfrom the connector housing and can be pushed back against the pressureof a spring (44 in FIG. 1 or 144 in FIG. 3), which at the front end hasa bore for the fiber. Provided laterally on the outside of the guidingsleeve is a covering in the form of a flexible sheet-metal strip. In thenon-inserted state, the covering projects with the front end over thebore in such a way that the bore is closed. When the connector isinserted into a coupling part, the covering is displaced against aspring action (rearward or transversely) in such a way that the bore inthe guiding sleeve is released. A disadvantage of this solution is thatthe guiding sleeve is not protected against mechanical effects when aconnector is not inserted. Furthermore, the laterally providedsheet-metal strip prevents the guiding sleeve from being used forcentering the connection when the connector is inserted. A forceoriented transversely to the direction of insertion is also exerted onthe guiding sleeve when the covering is actuated, and can easily lead tomalfunctions. In addition, this protective mechanism is not suitable forconnectors in which a ceramic ferrule into which the fiber is adhesivelyembedded by the end is provided instead of the guiding sleeve.

SUMMARY OF THE INVENTION

[0008] It is therefore the object of the invention to provide aconnector system which avoids the disadvantages of known systems and, inparticular with a simple and space-saving construction of the coveringmechanism, is distinguished by high functional reliability.

[0009] The object is achieved by the features of claim 1 in theirentirety. The essence of the invention is to divide the covering meansinto a first covering element, which protects the end of the opticalfiber in the axial direction and can be displaced transversely to theaxis, and a second covering element, which protects the end of theoptical fiber projecting from the housing in the radial direction andcan be displaced rearward parallel to the axis, and which has a firstpassage for the end of the optical fiber, the first passage being ableto be closed by the first covering element. The division has the effectof producing simplified movement sequences for the two coveringelements. At the same time, the division permits a space-savingarrangement and separate optimization of the functions.

[0010] The covering mechanism becomes particularly compact if, accordingto a first preferred refinement of the invention, the first coveringelement is arranged displaceably on the second covering element, if thefirst covering element is formed as a shutter, which is mounteddisplaceably transversely to the axis in a guideway formed in the secondcovering element, if, outside the region of the first passage, theguideway bends around in an arc rearward in a direction lying parallelto the axis, and if, for opening and closing the shutter, the shutter isdisplaced with its rear end parallel to the axis.

[0011] The automatic closing of the shutter is preferably brought aboutby the shutter being biased in the closed direction by a spring element,preferably in the form of a compression spring.

[0012] A particularly simple and effective mechanism for opening theshutter is obtained if, according to another preferred refinement of theinvention, the shutter is fastened by its rear end to a slide, which ismounted displaceably in the direction of the axis in the housing of theconnector, and if engaging means by which the slide is displacedrearward when the connector is inserted into the coupling are providedon the coupling and on the slide. In this case, the engaging meanspreferably comprise two actuating cams arranged on the inner sides ofthe side walls of the coupling and also two hook-shaped drivers, whichare arranged on the sides of the slide and come into engagement with theactuating cams when the connector is inserted into the coupling.

[0013] For reliable prevention of a disturbing reflection of lightthrough the closed shutter back into the optical fiber, it is ofadvantage if, in the region of the first passage, the guideway runsslightly at an angle to the axis.

[0014] The covering mechanism of the invention can be realizedparticularly simply if the second covering element is formed as aflap-shaped cover, and the guideway for the shutter is formed betweenthe cover and a holder which is provided with a second passage and isfitted into the cover.

[0015] For opening the second covering element, in the coupling there ispreferably a stop against which the second covering element or the coverbutts, and by which the second covering element or the cover is pushedback rearward, thereby releasing the end of the optical fiber, when theconnector is inserted into the coupling.

[0016] For closing the second covering element, in the coupling and onthe second covering element or the cover there are preferably latchingmeans which latch the second covering element or the cover to thecoupling when the connector is completely inserted into the coupling,and securely hold the second covering element or the cover in thecoupling when the connector is pulled out of the coupling, until therelative displacement between the second covering element or the coverand the housing of the connector causes the end of the optical fiber tobe covered again in the radial direction. The latching means preferablycomprise a detent provided on the second covering element or cover andalso a closure flap, the closure flap being pivotably arranged in thecoupling by means of a pivot bearing lying transversely to the axis andclosing the coupling when the connector is not inserted, and the closureflap being pivoted up and latching with its free end behind the detentby insertion of the connector into the coupling.

BRIEF EXPLANATION OF THE FIGURES

[0017] The invention is to be explained in more detail below on thebasis of exemplary embodiments in conjunction with the drawing, inwhich:

[0018]FIG. 1 shows a longitudinal section through a connector accordingto a preferred exemplary embodiment of the invention in the non-insertedstate with the covering device closed;

[0019]FIG. 2 shows in an exploded representation the individual parts ofthe connector according to FIG. 1;

[0020]FIG. 3 shows in a representation comparable to FIG. 1 theconnector from FIG. 1 inserted into the coupling, with the coveringdevice opened;

[0021]FIGS. 4 and 5 show in another sectional representation thefunction of the locking mechanism acting between the two coveringelements of the covering device.

WAYS OF IMPLEMENTING THE INVENTION

[0022]FIG. 1 shows a longitudinal section through a connector accordingto a preferred exemplary embodiment of the invention in the non-insertedstate with the covering device closed. The connector 10, the individualparts of which are also represented with the same reference numerals inFIG. 2, has an elongate housing 11, which is produced as aninjection-molded part from a suitable plastic and extends in thedirection of an axis 49. The axis 49 is at the same time the opticalaxis for the optical fiber (not shown in FIG. 1) and, in addition,indicates the direction of insertion in which the connector 10 isinserted.

[0023] Running coaxially in relation to the axis 49 through the housing11 is a bore 12, which receives the optical cable or the optical fiber.At the front end (on the left in FIG. 1) and at the rear end (on theright in FIG. 1) of the connector 10, the bore 12 respectively goes overinto a widened portion 17 and 18 with an enlarged inside diameter. Intothe first widened portion 17 there projects a cylindrical ferrule 23, inthe central bore 24 of which the end of the optical fiber is adhesivelyembedded in such a way that the end face of the fiber terminates withthe convex end face of the ferrule 23.

[0024] The ferrule 36 is seated with the rear end in a ferrule holder22, which is mounted displaceably in the direction of the axis 49 in thebore 12 and can be pushed rearward against the pressure of a firstcompression spring 25. Fitted into the second widened portion 18 is aspindle 21, the sleeve-shaped rear portion of which is used for fixingthe optical cable and for pushing on an anti-kinking sleeve (comparableto FIG. 14 of WO-A1-00/16145). Also formed on at the rear end of thehousing 11 is a forwardly extending, flexible latching arm 19, whichserves for fixing the inserted connector 10 (see FIG. 3). The latchingarm 19 has at its front free end two latching hooks 20, the function ofwhich is discussed in more detail further below in conjunction with FIG.3.

[0025] Provided at the front end of the connector, in the region of theferrule 23, is a protecting and covering device, which substantiallycomprises two covering elements. The one covering element is acap-shaped cover 30 with a central passage (36 in FIG. 2). The cover 30is mounted displaceably in the direction of the axis 49 at the front endof the housing 11 and is pushed back rearward over the ferrule 23,thereby releasing the front end of the ferrule 23, when the connector 10is inserted into the associated coupling (40 in FIG. 3).

[0026] The cover 30—when it is not pushed back—protects the ferrule 23projecting from the widened portion 17 in the radial (lateral)direction. For the protection of the ferrule 23 in the axial direction(from the front), a shutter 32 (see also FIG. 2) is provided as theother covering element in the form of a rectangular, flexibly bendablesheet-metal strip, which is guided on the cover 30 in a guideway 31. Theguideway 31 is formed by a holder 29 of an adapted shape, with acomparable passage (35 in FIG. 2) being fitted into the cover 30 fromthe rear, thereby maintaining a small distance which corresponds to thewidth of the guideway 31.

[0027] In the region of the first passage 36, the guideway 31 runssubstantially perpendicularly to the axis 49. However, it deviates fromthe perpendicular to the extent that a reflection of light through theshutter 32 back into the optical fiber is reliably prevented. Outsidethe region of the first passage 36, the guideway 31 bends around in anarc rearward in a direction lying parallel to the axis 49. The shutter32 guided in the guideway 31 is correspondingly bent. This achieves theeffect that opening and closing of the shutter 32 is performed bydisplacing the rear end of the shutter 32 parallel to the axis 49.

[0028] The shutter 32 is fastened by the rear end to a slide 26, whichis mounted displaceably in the axial direction in the upper part of thehousing 11 in a slot-shaped clearance 13 and can be pushed back rearwardagainst the pressure of a second compression spring 27. The slide 26 hason the upper side a holding cam 28, which reaches through acorresponding hole 48 in the shutter 32. Formed on two opposite sides ofthe slide 26 are flat arms 33, which project to the outside throughlateral slots 14 in the housing 11. Formed on the outer ends of the arms33 are hook-shaped drivers 34, which come into engagement with actuatingcams (43 in FIG. 3), fixedly provided on the inner walls of the coupling40, when the connector 10 is inserted into the coupling 40. The slide 26is consequently pushed back relative to the housing 11 on insertion andthe shutter 32, pulled back with the slide 26, releases the firstpassage 36. If the connector 10 is pulled out of the coupling 40 again,the compression spring 27 pushes the slide 26 back in the forwarddirection and the shutter 32 closes the first passage 36 again.

[0029] The actuation of the cover 30, which—as explained further belowon the basis of FIGS. 4 and 5—is performed in accordance with theactuation of the shutter 32, can be explained on the basis of FIG. 3,which shows a connector 10 completely inserted into the coupling 40. Ofthe coupling 40, only that part (the right-hand part) which is necessaryfor the connector 10 inserted from the right of the connector system 47is represented in FIG. 3. For a second connector, inserted from theleft, there is also a second, mirror-inverted (left-hand) part (see forexample FIG. 21 of WO-A1-00/16145). The coupling 40 has in the center abush mounting 41, which is coaxial to the axis 49 and into which aceramic sleeve for guiding the ferrules of the two connectors can beinserted. The bush mounting 41 is held by a wall which is arrangedperpendicularly in the centre and forms a stop 42 for the cover 30 ofthe inserted connector 10. If the connector 10 is then inserted into thecoupling 40, firstly the lateral actuating cams 43 (depicted in FIG. 3for clarification—although they are not visible) come into engagementwith the drivers 34 of the slide 26. The slide 26 moves back in theclearance 13 and draws up the shutter 32 over the first passage 36. Thecover 30 is in this phase hindered in a drawing-back movement by alocking mechanism described further below. Once the first passage 36 isfree and the locking is unlocked, as it is inserted further theconnector 10 butts with the cover 30 against the stop 42 of the coupling40 and the cover 30 is pushed back, until the front end of the ferrule32 is free, as shown in the representation in FIG. 3.

[0030] For the pushing forward of the cover from the pushed-backposition shown in FIG. 3, a special latching mechanism, which isrepresented in FIG. 3, is provided. Belonging to this latching mechanismare two detents 38, arranged on the upper side of the cover 30, and aclosure flap 45. The closure flap 45 is articulated pivotably in theinterior of the coupling 40 by means of a pivot bearing 46 orientedtransversely to the axis 49. When the connector 10 is inserted into thecoupling 40, the closure flap 45 is pivoted up against the pressure of aspring and, after complete insertion of the connector 10, latches withthe free edge, lying on a supporting surface 39, behind the detents 38(FIG. 3). If the connector 10 is pulled out of the coupling 40 again,the latched closure flap 45 keeps the cover 30 fixed or back, until itis lifted over the detents 38 by an unlocking cam 16, which is formed onan attachment 15 of the housing 11 and slides back with the housing 11,and releases the cover 30. In order that the unlocking cam 16 can movefreely in relation to the cover 30, a clearance 37 is provided betweenthe detents 38.

[0031] For the locking of the inserted connector 10 in the coupling 40,the already mentioned flexible latching arm 19 is provided with thelatching hooks 20, arranged at its free end. When the connector isinserted, the latching arm 19 latches with the latching hooks 20 behindtwo detents 44 formed on the inner edge of the coupling 40. Forunlocking, the latching arm 19 must then be pressed down, until thelatching hooks 20 come free from the detents 44.

[0032] The already mentioned locking of the cover 30 by the slide 26 canbest be explained on the basis of another sectional representation, asrepresented in FIGS. 4 and 5 for the locked and unlocked states.Essential elements of the locking mechanism are two locking levers 50(FIGS. 2, 4 and 5), which are formed on the housing 11, extend parallelin the axial direction, can be deflected resiliently downward, arearranged on the lower inner edges of the slots 14 and respectively beara cam 51 on the upper side. Left free underneath the locking levers 50there is respectively a slot-shaped intermediate space 52, which, whenthe cover 30 is pushed back, can receive tongues 53 formed on the holder29 and designed in such a way as to fit the intermediate space 52.

[0033] In the unplugged state of the connector 10, as represented inFIG. 4, the slide 26 is located with its arms 33 directly above the cams51 of the locking levers 50. As a result, the locking levers 50 aredeflected resiliently downward and prevent the tongues 53 of the holder29 from entering the intermediate spaces 52 lying thereunder. The holder29, and consequently also the cover 30, are thereby effectivelyprevented from yielding in this phase.

[0034] If, when the connector 10 is inserted, the slide 26 with theshutter 32 is pushed back in the way described further above to theextent that the passage 36 for the ferrule 23 is released, the cams 51are released and the locking levers 50 can pivot back into their axiallyparallel position of rest. The intermediate spaces 52 lying thereunderare then released, so that the holder 29 can enter with its tongues 53into the intermediate spaces 52 and the cover 30 can correspondinglymove back and release the ferrule 23 (FIG. 5).

List of Designations

[0035] 10 connector 11 housing 12 bore 13 clearance (slot-shaped) 14slot 15 attachment 16 unlocking cam 17, 18 widened portion 19 latchingarm 20 latching hook 21 spindle 22 ferrule holder 23 ferrule 24 bore 25,27 compression spring 36 slide 20 holding cam 29 holder 30 cover 31guideway 32 shutter 33 arm 34 driver (hook-shaped) 35, 36 passage 37clearance 38, 44 detent 39 supporting surface 40 coupling 41 bushmounting 42 stop 43 actuating cam 45 closure flap 46 pivot bearing 47connector system 48 hole 49 axis 50 locking lever 51 cam 52 intermediatespace (slot-shaped) 53 tongue (rigid)

1. A fiber-optical connector system (47), comprising a fiber-opticalconnector (10) and a coupling (40), into which the connector (10) can beinserted to establish an optical connection, the connector (10) having ahousing (11) which extends along an axis (49) and in which an opticalfiber is arranged such that it lies in the axis (49) and projects withone end from the end face of the housing (11), and means (30, 32) beingprovided for covering the end of the optical fiber, which means protectthe end of the optical fiber against external effects when the connector(10) is not inserted and release the end of the optical fiber projectingfrom the housing (11) when the connector (10) is inserted into thecoupling (10), characterized in that the covering means (30, 32)comprise a first covering element (32), which protects the end of theoptical fiber in the axial direction and can be displaced transverselyto the axis (49), and in that the coupling means (30, 32) comprise asecond covering element (30), which protects the end of the opticalfiber projecting from the housing (11) in the radial direction and canbe displaced rearward parallel to the axis (49), and which has a firstpassage (36) for the end of the optical fiber, the first passage (36)being able to be closed by the first covering element (32).
 2. Theconnector system as claimed in claim 1, characterized in that the firstcovering element (32) is arranged displaceably on the second coveringelement (30).
 3. The connector system as claimed in claim 2,characterized in that the first covering element is formed as a shutter(32), which is mounted displaceably transversely to the axis (49) in aguideway (31) formed in the second covering element (30).
 4. Theconnector system as claimed in claim 3, characterized in that, outsidethe region of the first passage (36), the guideway (31) bends around inan arc rearward in a direction lying parallel to the axis (49), and inthat, for opening and closing the shutter (32), the shutter (32) isdisplaced with its rear end parallel to the axis (49).
 5. The connectorsystem as claimed in claim 4, characterized in that the shutter (32) isbiased in the closed direction by a spring element, preferably in theform of a compression spring (27).
 6. The connector system as claimed ineither of claims 4 and 5, characterized in that the shutter (32) isfastened by its rear end to a slide (26), which is mounted displaceablyin the direction of the axis (49) in the housing (11) of the connector(10), and in that engaging means (34, 43) by which the slide (26) isdisplaced rearward when the connector (10) is inserted into the coupling(40) are provided on the coupling (40) and on the slide (26).
 7. Theconnector system as claimed in claim 6, characterized in that theengaging means comprise two actuating cams (43) arranged on the innersides of the side walls of the coupling (40) and also two hook-shapeddrivers (34), which are arranged on the sides of the slide (26) and comeinto engagement with the actuating cams (43) when the connector (10) isinserted into the coupling (40).
 8. The connector system as claimed inone of claims 3 to 7, characterized in that, in the region of the firstpassage (36), the guideway (31) runs at such an angle to the axis (49)that a reflection of light through the shutter (32) back into theoptical fiber is reliably prevented.
 9. The connector system as claimedin one of claims 3 to 8, characterized in that the second coveringelement is formed as a flap-shaped cover (30), and in that the guideway(31) for the shutter (32) is formed between the cover (30) and a holder(29) which is provided with a second passage (35) and is fitted into thecover (30).
 10. The connector system as claimed in one of claims 1 to 9,characterized in that in the coupling (40) there is a stop (42) againstwhich the second covering element or the cover (30) butts, and by whichthe second covering element or the cover (30) is pushed back rearward,thereby releasing the end of the optical fiber, when the connector (10)is inserted into the coupling (40).
 11. The connector system as claimedin claim 10, characterized in that a locking mechanism (50, 51, 52, 53)which only allows displacement of the second covering element (30) whenthe first covering element (32) has released the end of the opticalfiber is provided.
 12. The connector system as claimed in either ofclaims 10 and 11, characterized in that in the coupling (40) and on thesecond covering element or the cover (30) there are latching means (38,45, 46) which latch the second covering element or the cover (30) to thecoupling (40) when the connector (10) is completely inserted into thecoupling (40), and securely hold the second covering element or thecover (30) in the coupling (40) when the connector (10) is pulled out ofthe coupling (40), until the relative displacement between the secondcovering element or the cover (30) and the housing (11) of the connectorcauses the end of the optical fiber to be covered again in the radialdirection.
 13. The connector system as claimed in claim 12,characterized in that the latching means comprise a detent (38) providedon the second covering element or cover (30) and also a closure flap(45), the closure flap (45) being pivotably arranged in the coupling(40) by means of a pivot bearing (46) lying transversely to the axis(49) and closing the coupling (40) when the connector (10) is notinserted, and the closure flap (45) being pivoted up and latching withits free end behind the detent (38) by insertion of the connector (10)into the coupling (40).